The Idol then shared some news with the roaring crowd. "I'm going to be involved for the third year in a row, actually, with Race for Hope in Washington D.C." Cook, 28, said. "It's a 5K walk/run and all the proceeds go to an organization called ABC Squared [Accelerated Brain Cancer Cure or ABC2.org] that I've been involved with now for a while to help find a cure for brain cancer."

Cook's older brother Adam, who was often in the front row cheering him on during his winning season, lost a decade-long battle against brain cancer in 2009.

When Seacrest said he noticed Cook's mother Beth in the crowd Thursday night, the singer explained: "I told her that we were coming back to play the new single and it will be really interesting," he said. "[She said], 'I just want to meet Steven Tyler, that's it.' So, I figured while I have the forum we should ... Do you want to say hi or something?"

At that point Cook's mother got out of her seat and went to greet the Idol judge. They embraced and even shared a kiss on the cheek.

"Do you approve?" Seacrest asked.

Cook shook his head and said, jokingly, "We're going to have a conversation when the cameras go off."